JP2514956Y2 - Constant velocity joint - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a constant velocity joint used for propeller shafts and drive shafts of automobiles.

[Conventional technology]

Generally, constant velocity joints for propeller shafts improve rotational balance performance and various NVH performance.
It is often used in the state where there is no joint clearance by applying a preload to the constant velocity joint. In addition, even in constant velocity joints for drive shafts, in order to improve various NVH performance, they may be preloaded and used without joint looseness.

A ball type constant velocity joint is used for the propeller shaft and the drive shaft.

4 to 6 show various ball type constant velocity joints, and each constant velocity joint is composed of an outer ring 1, an inner ring 2, a cage 3 and a plurality of balls 4, and the inner surface of the outer ring 1 and the inner ring 2 are shown. Tracks T ₁ and T ₂ for guiding the movement of the ball 4 are provided on the outer surface of the.

Here, the joint shown in FIG. 4 is called a cross group joint, and the cage 3 has a cylindrical inner surface 5 of the outer ring 1.
There is provided a spherical outer surface 6 that is guided in contact with the inner ring 2, and a spherical inner surface 8 that faces the outer surface 7 of the inner ring 2.

The joint shown in FIG. 5 is referred to as a double offset joint, and the cage 3 is contacted and guided by a spherical outer surface 6'which is guided by the cylindrical inner surface 5'of the outer ring 1 and a spherical outer surface 7'of the inner ring 2. A spherical inner surface 8 ', and the center A ₁ of the spherical outer surface 6'and the center B ₁ of the spherical inner surface 8'of the cage 3 are offset from the center O _{1 of the} joint by the same distance to the left and right.

Further, the joint shown in FIG. 6 is called a bar field joint, and the center A ₂ of the track T ₁ formed on the spherical inner surface 5 ″ of the outer ring 1 and the center B of the track T ₂ provided on the spherical outer surface 8 ″ of the inner ring 2 are shown. ₂ is offset to the left and right from the joint center O ₂ .

Outer ring 1 and inner ring 2 of these ball type constant velocity joints
As shown in FIG. 7 (a), each of the tracks T ₁ and T ₂ has an angular contact track (AC track) (AC) having a fixed contact angle, and as shown in FIG. 8 (a), There is a circular contact track (CC) with a non-uniform contact angle.

When torque is transmitted to both tracks (AC) and (CC) with a constant velocity joint clearance, Fig. 7 (B)
Also, as shown in FIG. 8 (b), the AC track (AC) and CC track (CC) are in a two-point contact state, and the ball 4
Rolls correctly.

However, as shown in Fig. 9 and Fig. 10, when preload is applied to eliminate the joint clearance and torque is transmitted in that state, the AC truck (AC) operates in a 4-point contact state. There is a problem that friction increases due to slippage, which deteriorates temperature rise performance, durability, allowable rotation speed, and NVH performance.

On the other hand, the CC track (CC) operates in a two-point contact state, but at high load, the ball 4 against the CC track (CC)
The contact ellipse of (a) rides on the track (CC) and generates high surface pressure, or the shoulder (b) of the track (CC) is chipped, which deteriorates durability.

In order to solve the above problems, the applicant of the present application has already proposed a constant velocity joint in which an AC track and a CC track are mixed and a preload is applied to the CC track (Japanese Patent Application No. 1-31).
No. 4051).

According to the above-mentioned constant velocity joint, when torque is applied between the outer ring and the inner ring, the balls in the AC track act in a two-point contact state. Therefore, slip between the balls and the AC track should be prevented. It is possible to reduce the frictional force.

[Problems to be solved by the device]

By the way, in a constant velocity joint in which AC tracks and CC tracks are mixed and CC tracks are preloaded, AC constant
Since the track clearance is formed between the track and the ball, when torque is applied, the AC track does not receive the torque unless the CC track is elastically approached by an amount equivalent to the track clearance of the AC track. As a result, there are areas for improvement.

Therefore, in this invention, in a constant velocity joint in which AC trucks and CC trucks are mixed, both AC trucks and CC trucks are made to bear almost the same load, and temperature rise performance, durability, allowable rotation speed, The technical issue is to improve NVH performance.

[Means for solving the problem]

In order to solve the above problems, in this invention,
The inner surface of the outer ring and the outer surface of the inner ring are circumferentially provided with three sets of CC tracks and three sets of AC tracks that are opposed to each other in the joint radial direction, and the balls incorporated in the tracks of each set are the outer ring and the inner ring. It is held by a cage built in between, and a ball guide surface with a constant facing distance is formed in the center of the CC track in the circumferential direction that faces in the radial direction of the joint. Preload is applied and the circumferential track clearances formed between the CC track and the ball and the AC track and the ball are made approximately equal.

[Action]

With the above configuration, when torque is applied between the outer ring and the inner ring, the balls in the CC track and the balls in the AC track move in the circumferential direction by an amount equivalent to the track clearance and move to each track. Contact is made at two points, and torque is transmitted while a load is applied to each contact point.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS.

Incidentally, FIG. 1 is a sectional view of a constant velocity joint according to the present invention, and the overall structure is the same as that of the constant velocity joint shown in FIGS.

As shown in FIG. 1, three sets of CC tracks (CC) and three sets of AC tracks (AC) are alternately formed in the circumferential direction at the opposing positions of the inner surface of the outer ring 1 and the outer surface of the inner ring 2. A ball 3 for torque transmission incorporated in each track (CC) (AC) is supported by a cage 3.

Fig. 2 shows the details of the CC truck (CC), the outer ring side CC
A ball guide surface 10 is formed in the central portion in the circumferential direction of the track (CC) and the inner ring side CC track (CC) so that the facing distance in the joint radial direction is constant over the entire circumferential direction. A pair of arc-shaped ball rolling surfaces 11 are provided continuously at both ends in the direction.

In the embodiment, the ball guide surface 10 is connected to the center O of the joint.
Although the facing distance is kept constant as an arcuate surface having a center of curvature, the facing distance may be kept constant by using the ball guide surface 10 as a flat surface.

A radial preload is applied to the CC track (CC), and the ball guide surface 10 is pressed against the ball 4 by the preload, and a circumferential track clearance 12 is formed between the ball 4 and the ball rolling surface 11. ing.

On the other hand, the AC track (AC) has ball rolling surfaces 13 on both sides, and a circumferential track clearance 14 is provided between the ball rolling surface 13 and the ball 4. The circumferential track clearance 14 is substantially equal to the circumferential track clearance 12 of the CC track (CC).

As described above, the radial preload is applied to the three sets of CC tracks (CC), the radial play of the joint is eliminated, and when torque is applied to the inner ring 2 in the preloaded state, the CC tracks (CC Ball 4 and AC in CC)
The ball 4 in the track (AC) moves in the circumferential direction.

At this time, the track clearance 12 provided on the CC track (CC) and the track clearance formed on the AC track (AC)
Since 14 has almost the same size, the balls in the CC track (CC) and the balls 4 in the AC track (AC) are the balls of the CC track (CC) and the AC track (AC) as shown in FIG. The rolling contact surfaces 11 and 13 come into contact with each other substantially at the same time, and each contact portion bears the same circumferential load.

Therefore, there is no increase in surface pressure on the CC track (CC), and since the balls 4 in the CC track (CC) and the AC track (AC) operate in a two-point contact state, the ball 4 rolls correctly, Generation of heat and vibration due to friction can be suppressed.

In the case of the embodiment, three sets of six sets of tracks are CC tracks (CC) having a ball guide surface in the central portion in the circumferential direction, but the CC tracks (CC) are AC tracks (AC). It suffices if there are three or more pairs in a mixed state.

[Effect of the Invention] As described above, according to the constant velocity joint of the present invention, three sets of CC tracks and three sets of AC tracks are alternately provided in the circumferential direction, and the outer ring side and the inner ring side CC tracks are provided. A ball guide surface with a constant facing distance is formed in the central part in the circumferential direction, and radial preload is applied to the CC track to substantially eliminate the circumferential track clearance formed between the CC track and the ball and the AC track and the ball. Since the sizes are the same, the balls in the CC track and the balls in the AC track can be brought into a two-point contact state at substantially the same time when torque is applied.

Therefore, when torque is applied, the ball can always roll correctly regardless of the size of the load, and both CC track (CC) and AC track (AC) share an almost equal circumferential load. It is possible to improve temperature rise performance, durability, allowable rotation speed, and NVH performance. Further, since the balls are preloaded by the dimensional control of the CC contact track, parts such as springs are not required, and a constant velocity joint that is easy to assemble and low in cost can be provided.

[Brief description of drawings]

1 is a sectional view showing an embodiment of a constant velocity joint according to the present invention, FIG. 2 is an enlarged sectional view showing a track portion of the same, and FIG. 3 is a sectional view showing an operating state of the same. 4 to 6 are vertical sectional front views showing constant velocity joints of various ball types, FIGS. 7 (a) and 8 (a) are cross-sectional views showing examples of trucks, and FIG. 7 (b). And FIG. 8 (b) is a sectional view showing the operating state of FIG. 7 (a) and FIG. 8 (a), FIG. 9 is a sectional view of the AC track preloaded, and FIG. 10 is a CC track. It is sectional drawing of the state where the preload was applied. 1 ... Outer ring, 2 ... Inner ring, 3 ... Retainer, 4 ... Ball, AC ... Angular contact track, CC ... Circular contact track, 10 ... Ball guide surface, 11 ...
… Ball rolling surface, 12,14 …… Track clearance.

Claims (1)

(57) [Scope of utility model registration request] 1. Three sets of circular contact tracks and three sets of angular contact tracks, which are opposed to each other in the joint radial direction on the inner surface of the outer ring and the outer surface of the inner ring, are alternately provided in the circumferential direction, and are incorporated in the tracks of each set. The ball is held by a cage installed between the outer ring and the inner ring, and a ball guide surface with a constant facing distance is formed in the circumferential center of the circular contact tracks that face each other in the radial direction of the joint. A constant velocity joint characterized in that a radial preload is applied between the ball and the circular contact track and the angular contact track so that the circumferential track clearances with respect to the ball are substantially equal.